Electric furnace

ABSTRACT

An electric air heater is provided with a cabinet enclosing a heating chamber having top, bottom and sidewalls. The heating chamber houses an open-ended cylindrical heat exchanger positioned so as to absorb heat from a plurality of lamps mounted at the junctures of the sidewalls. A fan is provided to pump air from a cabinet air inlet into an air inlet in the bottom wall. The air is pumped into and around the heat exchanger, over the lamps and out an air outlet in the top wall. The cabinet is kept cool by passing the cool incoming air through a tortuous air flow ducts surrounding the heating chamber before the air flows into the chamber. The heat exchanger is provided with a plurality of inwardly directed ferrous rod members secured to the heat exchanger by a dome-shaped bronze weld.

United States Patent [72] Inventor Darrell W.Covau1t Kingman, Ind. (R.R. #1, Box 3 Vcedersburg, Ind. 47987) [21] AppLNo. 755,604 [22] Filed Aug.27, 1968 [45] Patented Apr. 20, 1971 [541 ELECTRIC FURNACE 3 Claims, 7 Drawing Figs.

[52] 1.1.8.6] 219/368, 165/122,165/179, 219/370, 219/376 [51] 1nt.Cl. F24h 3/04, 1-105bl/00 [50] Fieldol'Search 219/365- [56] References Cited UNITED STATES PATENTS 1,444,621 2/1923 Lynnetal 219/368X 1,534,571 4/1925 Conning 219/368 1,694,351 12/1928 Long 219/3 68 X 2,527,013 10/1950 Kjelgaard....

Primary Examiner-A. Bartis Attorneys- Clarence A. OBrien and Harvey B. Jacobson ABSTRACT: An electric air heater is provided with a cabinet enclosing a heating chamber having top, bottom and sidewalls. The heating chamber houses an open-ended cylindrical heat exchanger positioned so as to absorb heat from a plurality of lamps mounted at the junctures of the sidewalls. A fan is provided to pump air from a cabinet air inlet into an air inlet in the bottom wall. The air is pumped into and around the heat exchanger, over the lamps and out an air outlet in the top wall. The cabinet is kept cool by passing the cool incoming air through a tortuous air flow ducts surrounding the heating chamber before the air flows into the chamber. The heat exchanger is provided with a plurality of inwardly directed ferrous rod members secured to the heat exchanger by a dome-shaped bronze weld.

Fig 3 PATENTEDAPRZOIQYI 3.575.582

' SHEET 2 OF 4 Darrell W. Covau/f INVIz'N'l'OK.

min #0004 29% PATENTED APRZO 1am SHEET 0F 4 Fig .5

Darrell W. Covau/f IN VIiN'I'OK ELECTRIC FURNACE Heretofore, electric heaters have been relatively inefficient in that the heat gained from them was only that of the heat radiated from the initial source. Some improvement was made upon the simple heat source by inducing a fan to pass more air around the heat source to thereby attempt to heat more air. While the latter was some improvement, large heat gains were experienced in a relatively small area while areas beyond the high heat gain area were relatively cool.

The present invention relates to an electric heater that achieves a high degree of efficiency by confining an infrared heat source and a heat exchanger in a chamber through which air to be heated is passed. The air to be heated is pumped through the chamber which exposes a greater'area of heated surface to the passing air thereby causing the air passing therethrough to pick up more heat and hence the high efiiciency of the unit. The construction of the heat exchanger unit, comprising a cylindrical wall with interior extending projections, presents a large area of heated surface to the air passing therethrough. In addition to the large area of the heat exchanger unit the air passing therethrough is also forced to pass around the heating units and the confining chamber walls thus further increasing the area of heat over which the air must pass. The design of the actual heating chamber, which contains the heat exchanger unit and the heat source, allows a functional appearing unit to be constructed which confines the heating elements within the interior of the unit so that there is no danger of burning or scorching of objects that may come into contact with the heating unit. This design further allows the unit to be enclosed in a decorative cabinetry and thereby avoid the unsightly space heaters as has been heretofore known. I

It is therefore an object of this invention to provide a simple but unique and highly efficient electric heater.

It is a further object of this invention to provide a heater wherein the amount of heat transferred from the heat source is accomplished by passing the air through a heat exchanger before releasing the air to the room in which the heater is located.

It is a further object of this invention to provide a heating unit wherein the heating elements and the heat exchanger are enclosed in a chamber to provide an extremely large amount of heated surface over which air to be heated is passed.

It is a further object of this invention to provide a heating device wherein'the mechanism for heating is enclosed within the device thereby preventing the exposure to nearby objects of the intense heat from the heating elements.

It is a still further object of this invention to provide a heating unit whose enclosure of the heating mechanism lends itself to being enclosed within a decorative cabinet.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIG. 1 is a perspective view of the subject heating device.

FIG. 2 is a sectional view taken substantially along the line 2-2 of FIG. 1.

FIG. 3 is a sectional view taken substantially along the line 3-3 of FIG. 1.

FIG. 4 is a perspective view of a modification of the basic heating device.

FIG. 5 is a sectional view taken substantially along the line 5-5 of FIG. 4.

FIG. 6 is a sectional view taken substantially along the line 6-6 of FIG. 5.

FIG. 7 is an enlarged sectional view showing the detail of the attachmentof the spokes into the heat exchanger wall.

Referring now to the drawings, numeral 10 generally designates the heating device with numeral 12 designating the cabinet structure and numeral 14 designating the heating chamber. The cabinet structure 12 comprises an elongated four-sided box with a top thereon, the elongated box section having opposed sides 16, a front side 18 and a rear side 20. The opposed sides 16 are rectangular extending members with an opening 22 near the top edge thereof which is covered by a grill 24 with vanes 26 therein to deflect the flow of 'warm air therethrough. The front side 18 of the cabinet structure has an opening 28 near the bottom thereof which is the air inlet and is covered by a grill 24 with the vanes 26 therethrough to direct the flow of air thereinto. The front side 18 has a further opening 30 near the top edge thereof to provide an additional outlet for the warm air. The opening 30 is closed by another grill 24 with vanes 26 thereacross. The rear side 20 of the cabinet structure has an opening 32, similar to the openings 22 and 28, near the top edge thereof which is closed by a grill 24, with vanes 26 thereacross to guide the warm air going through the outlet grill. A large rectangular opening 34 is aligned about the center of the rear side 20 to provide access to the interior thereof. The large rectangular opening 34 is closed by an access door 36 which overlies the opening and is fastened thereto by a plurality of screws 38. Mounted on the rear side 20 immediately below the access opening 34, and the door 36 thereon, is the switch 40 which is of the heavy duty type to handle the 220 volt line necessary to power the device. Adjacent the switch 40 is an aperture 42 through which the power cord 44 extends to enter the switch from the rear thereof. The cabinet structure as thus described presents an elongated rectangular column with four sides providing the enclosure, with the four warm air outlets adjacent the top edge of each of the sides, and the cool air inlet at the base of the front side. The top of the cabinet is closed by a cover member 46 which is square in outline to conform to the cross section of the cabinet. The cover member 46 has a flat platelike top surface 48 with four depending sides 50 attached thereto. The depending sides 50 overlie a small portion of the upper edge of each of the four sides and are attached thereto by screws 52 extending through threaded openings in the depending sides 50 and the top edges of the sides. An enlarged opening 54 of circular cross section is cut into the middle of the top surface 48 to provide an additional outlet for the heated air that emanates from the heating device. The opening has a deflector plate 56 held above the opening 54 in spaced relation by leg members 58 to deflect the air horizontally into the room so as to gain the most benefit therefrom. As can be seen from the above, all of the warm air outlets deflect the warm air horizontally into the room to prevent the warm air from immediately rising to the top or ceiling portion of each room to thereby lose most of the heating benefit therefrom.

The heating chamber 14 is mounted concentrically of the cabinet and comprises a substantially rectangular chamber 60 with the flat sides thereof being parallel to the exterior sides of the cabinet. The rectangular chamber 60 is supported within the cabinet on a floor unit 62 which comprises a square upper plate 64 and a square lower plate 66. The two floor plates, 64 and 66, are held in spaced relation by depending walls 68 on the four sides thereof. This then creates an air gap 70 to insulate the heating chamber from the surface on which the heating device will rest. The floor unit 62 is attached between the four sidewalls of the cabinet just above the cool air inlet opening 28, with the floor unit having concentric openings 72 in the upper and lower tloor plates to permit the cool air to enter thereinto. The rectangular chamber 60 is further held in its concentric relationship with the cabinet by an upper plate member 74 which is fixed between the four sides adjacent the top thereof. A depending cylindrical wall 76 is fixed to the opening 54 in the top and fixed at its lower edge to the plate 74 thereby providing an air space 78 between the plate 74 and the top surface 48. A circular opening 80 is cut in the center of the plate 74 to align with the opening 54 in the top plate, but of smaller circumference so that warm air exiting the opening 80 will pass through the opening 54 and impinge on the deflector plate 56. The rectangular chamber 60 being fixed, as mentioned hereinabove, between the upper floor plate 64 of the floor unit and the upper plate member 74 in concentric relation to the cabinet, has two side members 82, a front side 84, and a rear side 86. The sides 82 are fixed in sealing engagement to the upper floor member 64 and extend upwardly and are fixed to the upper plate member 74 in similar sealing engagement, with a rectangular opening 88 near the top edge thereof of the same size and in alignment with the opening 22 in the sides of the cabinet 16. A rectangular duct 90 conforming to the size of the openings 22 and 88 is attached therebetween in sealing engagement to duct the air from the interior of the rectangular chamber 60 outwardly past the air gap created by the spaced relation of the sides 82 and 16. The front side M of the chamber 60 is similarly fixed to the upper floor plate 64 of the floor unit in sealing engagement therewith and at its upper edge to the upper plate member 74. The chamber 60 being fixed in concentric relation to the cabinet at similar air gap 92 is created between the front side of the chamber 60 and the front side of the cabinet structure. Near the upper edge of the front side 84 is a rectangular opening 94 of the same size as, and aligned with, the opening 30 in the front side of the cabinet. A rectangular duct 96 is fixed in sealing relation in the openings 30 and 94 to duct the warm air from the interior of the chamber past the air gap 92 and out the grill 24. The rear side 86 of the rectangular chamber is fixed along its bottom edge to the top or upper floor plate 64 of the floor unit and is fixed at its upper end to the upper plate member 74. The rear side 86 also being in spaced relation to the rear side 20 of the cabinet creates an air gap 97 therebetween to further insulate the heating chamber from the cabinet structure. A rectangular opening 98, of the same size and aligned with the opening 32 in the rear side of the cabinet structure, is cut therethrough and has a rectangular duct 100 fixed therebetween to duct the heated air from within the chamber past the air gap 97 and through the grill member 24. An enlarged rectangular opening 102 is cut through the back or rear side 86 of the heating chamber in alignment with the opening 34 in the rear side of the cabinet structure. This opening is provided so that when the enclosure member 36 is removed from the back side of the cabinet structure access can be gained therethrough into the interior of the heating chamber 60. To maintain the insulation provided by the air gap between the heating chamber and the cabinet structure a closure member 104 is provided to overlie and close the opening 102 which is held thereon by screws 106 which are received in threaded openings in the closure member 104 and the rear side 86. The sides 82, the front side 84 and the rear side 86 of the heating chamber 60 are joined by angled sides 108 set at an angle of 45 relative to each of the adjoining sides thereby providing four sides in a plane perpendicular to the diagonals of the square formed by the chamber. These sides 108 provide the mounting surface for the heating elements 110 which are conventional infrared lamp units. The heating elements 110 have their socket bases 112 mounted on the angled sides 108 in three horizontal rows thereby producing a total of 12 lamps 114 inserted in such sockets. The lamps 114 being mounted on the angled sides 108 face inwardly in opposed pairs thereby creating an open column down the center of the heating chamber. A heat exchanger unit 116 is mounted in the center thereof to absorb the heat radiated by the lamp units. The heat exchanger unit 116 comprises an elongated cylinder 118 open at both ends thereof. The cylinder 118 has a plurality of holes 120 drilled therein in horizontally disposed rows. A convenient number of holes per horizontal row has been found to be l as shown in FIG. 2. The holes 120 are punched inwardly providing a dimpled opening as shown in FIG. 7. A rod unit 122 with an enlarged head 124 thereon is inserted in each of the holes 120 and is held in fixed relation thereon by a dome-shaped weld 126 which completely envelopes the head 124 and a portion of the rod unit 122. The combination of materials found to be most beneficial for use in the heat exchanger unit has been when the elongated cylindrical unit 118 is made of a galvanized metal, with the rod units being of a ferrous alloy much like that used in the conventional nail, and where the dome-shaped weld is of bronze. The weld 126 is formed on the head in such a dome shape to provide a greater area to be exposed to the heat rays from the infrared lamps and thereby present a greater overall area within which to absorb the heat rays. Thus not only does the cylindrical wall 118 emanate heat into the path of the air but the rod units 122 break up the path of the air flowing therethrough and add further heat to the air as-it passes through. The heat exchanger unit 116 is held in place in the center of the lamp units by legs 128 attached to the cylindrical unit 118 and the upper floor plate 64 of the floor unit. Arranged in relatively coplanar relationship with the lower edge of the cylindrical unit 118 is a diffuser plate 130 which is held in the center thereof by an angular leg 132 to further diffuse the air passing therethrough so that a portion of the air passes through the heat exchanger and the remainder around it to insure that it is heated to the highest possible point and thereby increase the efficiency of the heating chamber.

A fan assembly 134 is attached to the lower floor plate 66 of the floor unit with a duct 136 attached between the cold air opening and the inlet of the fan. The fan discharges into a vertically extending duct 138 which is of substantially the same diameter as the openings 72 through the upper and lower floor plates. The duct 138 is sealed to the openings 72 in the floor unit thereby ducting the air past the air gap 70 and into the heating chamber. As the air enters therein, it is diffused by the plate 130 so that a portion of the air progresses up the inside of the heat exchanger unit thereby being warmed by the heat radiated from the walls and rod units mounted therein. The remaining portion of the air is diffused out to progress up the outer surface of the heat exchanger unit thereby being warmed by the outer circumference thereof, the chamber walls, and the heat directly radiated by the lamp units. All of the warm air then rises to the top of the heating chamber where it is dispersed out the four horizontally extending grills 24 with some portion thereof progressing through the opening 80 and out the opening 54 in the top surface to impinge on the deflector plate 56 to also be turned horizontally into the room. Thus, as set forth hereinbefore, all of the warm air emitted from the heating device progresses horizontally into the room to insure maximum heating effect gained therefrom and also the cooler air is drawn off the floor and into the heating device.

The wiring for the heat lamps is disposed in the air gaps that surround the heating chamber to thereby protect the wiring from the extreme heat generated within the chamber. Similarly the wiring for the fan 142 is located beneath the floor unit 62 thereby also protecting the wire from the heat within the chamber. The switch 40 turns on both the lamps and the fan and is of such a capacity as to handle the 220 volt line necessary to feed the twelve 350-watt lamps.

The modification shown in FIGS. 4 through 6 uses the same basic heating unit as the embodiment shown in FIGS. 1 through 3 except that additional ducting of the air is provided to cool the heating chamber so that a decorative cabinet of wood or other material may be used thereon. The cabinet structure comprises two side panels 152 and a front panel 154 of identical configuration and a rear panel 156. The panels 152 and 154 have a cutout 158 along the bottom edge thereof which leaves a portion of material 160 at each edge thereof which forms a leg unit. Near the top of each panel is a rectangular cutout 162 which has a grill unit 164 received therein. The grill unit 164 has a horizontal plate 166'which overlies the surface of the panel and a rectangular duct section 168 attached to the plate 166 in perpendicular relationship thereto and extends within the rectangular cutout 162. A series of vanes 170 are attached horizontally across the duct 168 to direct the flow of air therethrough. The rear panel 156 of the cabinet is essentially the same as the panels 152 and 154, in that it has a rectangular opening 172 near the top edge thereof and a grill unit 164 inserted therein. Similarly, at the bottom edge of the rear panel 70 a cutout 158 is cut therein leaving the leg portions 160 at either end of the cutout. An enlarged rectangular cutout 174 is aligned on the rear panel 156 of the cabinet to provide access to the interior thereof. The rectangular cutout 174 is closed by a panel 176 which overlies the cutout and is fastened thereto by a series of screws 178. The top of the cabinet is closed by a cover panel 180 which is fastened between the four panels of the cabinet and held in place therein by blocks 182 attached to the interior of the wall panel with the cover panel 180 resting thereon to facilitate the installation. As can be seen from the construction of the cabinet, when it sits on the floor, the four cutouts 158 on each of the wall panels provide the inlet for the air to go into the heating unit, while the four grill units 164 provide the heated air outlet which directs the air horizontally into the room. A series of eight angle corner brackets 184 are fixed on the interior of the cabinet where the wall panels meet to fix the panels there together and provide additional bracing. The corner brackets are arranged in two series of four brackets with the four brackets of a series in a horizontal plane in the cabinet. The first series of four brackets are located near the bottom of the wall panels above the cutouts 158 therethrough. The upper series of brackets are located just beneath the rectangular cutouts for the grills, and thereby provide support for the connecting ductwork as well as bracing the wall panels.

The heating chamber and its ductwork is located concentrically within the cabinet structure and is supported on a floor unit 186 in the lower portion of the cabinet. The floorunit comprises two angular-shaped support members 188 which are affixed to thefront and rear panels of the cabinet immediately above the corner brackets 184. The floor unit further comprises two support members 190 which extend completely across the cabinet from front to rear and are attached to the angular supporting members 188. The support members 190 have a floor plate 192 fixed in the center thereof in concentric relation with the four panels of the cabinet. The area of the floor plate 192 is less than the interior cross-sectional area of the cabinet so as to produce a gap around the four sides thereof. An elongated rectangular duct 194 is attached to the floor plate 192 and extends upwardly to a point spaced below the upper series of angular comer brackets. The duct 194 has an elongated rectangular opening 196 in the side thereof facing the rear panel of the cabinet structure, so that when the closure panel on the rear of the cabinet structure is removed access can be gained therethrough. The rectangular opening 196 has a closure panel 198 fastened thereon by means of screws 200 to close the opening when access therethrough is not desired. A heating chamber 60 substantially the same as that shown in the embodiment of FIGS. 1 through 3 is mounted in concentric relation to the rectangular duct 194. The heating unit 60 has a single floor member 202 in this embodiment and is supported in parallel spaced relation to the floor plate 192 by leg units 204. The single floor unit 202 has a central opening 206 therethrough which conforms to the opening 72 in the previous embodiment. The heating chamber is aligned in the rectangular duct 104 so that the rectangular opening 102 in the rear side of the heating chamber is aligned with the openings 1% in the duct 194 and the opening 174 in the rear panel of the cabinet. The aligning of the three openings thereby allows easy access to the interior of the heating chamber for changing of lamps and other routine maintenance. The walls 32, 84 and 86 of the heating chamber extend upwardly and are fastened to a heating chamber cover plate 208 which is installed just below the blocks 182 which support the cover panel of the cabinet. Thus an air gap 210 is created between the top of the heating chamber and the cover panel of the cabinet. A rectangular opening 212 is cut into each of the four sides of the heating chamber opposite the openings 162 in the cabinet panels and are of the same size and in alignment therewith. The openings 212 have a perpendicularly extending flange 214 attached thereto, with a rectangular duct 216 extending between the flange 214 and the duct section 168 of the grill unit 164. Withthe proximity of the upper series of corner brackets 184 the ducts 216 can be supported thereon to add additional rigidity to the installation thereof. immediately below the four openings 212 in the heating chamber walls, a baffle plate 218 is installed to slow down the passage of air through the heating chamber so that the maximum heating effect can be gained thereby. The baffle plate 218 has a circular opening 220 in the middle thereof to pass the heated air therethrough, to be then dispersed through the four outlets in the wall. A fan assembly 222, to force the air through the heating chamber, is mounted on the floor unit 202 with the outlet side thereof fastened to alignment with the central opening 206 through the plate. The inlet 224 of the fan unit draws its air from the chamber between the floor plate 192 and the floor unit 202. The airflow is the same through the heating chamber, since the heating chamber is the same as the first embodiment, with the air being forced through the opening 206 and impinging on the diffuser plate where a portion of the air progresses up the interior of the heat exchanger unit 116 with the remaining portion of the air flowing up the outside of the heat exchanger unit around the heat lamps.

As can be seen from the above description, the instant embodiment is meant to provide for keeping the exterior or wooden cabinet cool by ducting the air through a tortuous path through the interior of the cabinet before it reaches the heating chamber. In operation, the cool air to be heated flows through the four openings, formed by the cutouts 156, around the base of the cabinet from whence it proceeds upwardly around the floor plate 192 to progress up the duct created by the space between the elongated rectangular duct 194 and the cabinet structure. At the top of this duct, the air is turned around the top of the rectangular duct 194 where it proceeds downwardly along the duct created by the walls of the heating chamber 60 and the walls of the rectangular duct 194. The air then is received in the enlarged chamber between the floor plate 192 and the floor unit 202 where the fan draws it in and forces it up through the interior of the heating chamber. The heating chamber being the same as in the first embodiment the same high efficiency is achieved and the heated air is forced through the opening 220 in the baffle plate 218 where it impinges on the heating chamber cover plate 208 and then proceeds out the four horizontally extending ducts 216 to exit the grill units 164.

As can be seen from the two embodiments set forth herein, the unique heat exchanger unit is the common feature of both embodiments and provides the extremely high efficiency obtained by the heating units. The large area of the heated metal created by the circular heat exchanger and the inwardly extending rod units and the walls of the chamber provide a degree of efficiency not heretofore attainable with electric heaters.

I claim:

1. In an electric furnace, the combination of a vertically elongated casing including aset of sidewalls and a top and bottom provided with an air inlet and an air outlet opening respectively and a heat exchanger consisting of an elongated tubular member vertically disposed in said casing and in longitudinal alignment with said openings and having its upper and lower ends spaced from the respective top and bottom of the casing whereby to facilitate flow of air from the inlet to the outlet openings both interiorly and exteriorly of said tubular member, a cabinet enclosing said casing in concentric spaced relation thereto and including a bottom wall having an air inlet disposed outwardly of the air inlet in the casing and a top partition closing the space between the cabinet and easing, said cabinet having outlet means communicating with the air outlet in the casing, a baffle extending upwardly from the bottom wall of the cabinet inwardly of the air inlet therein and in spaced concentric relation to the casing and cabinet, the upper edge of the baffle terminating below the top partition to provide an air path, and airflow inducing means communicating with the air inlet in the bottom of the casing and the space between the lower portion of the baffle and the casing to induce a reverse flow of air around the top edge of the baffle and retaining the cabinet cool by insulating it from the casing and tubular member, electric heating means mounted at the intersection of said sidewalls and orientated toward said tubular heat exchange member for simultaneously heating the latter and allowing the air to flow exteriorly of the same, said tubular heat exchange member including a plurality of headed prong-shaped heat transmitting elements extending into the interior of said tubular member for heating the air flowing interiorly thereof, said prong-shaped elements being constructed of a ferrous alloy and welded to said tubular member with the head of the elements being engulfed in metal. 

2. An electrical furnace as disclosed in claim 1 wherein the prong-shaped elements extend radially inwardly in the tubular member and terminate in spaced relation to each other.
 3. The device of claim 2 wherein the metal weld engulfing the head of the prong-shaped elements being dome-shaped and of bronze thereby providing an extremely good heat conducting path from the electric heating means to the prong-shaped members within the tubular member. 